1. Field of the Invention:
This invention is concerned with substituted diphenyl ethers and their use as herbicides.
2. Description of the Prior Art:
It has been proposed to use as herbicides 2-methoxybenzoic acids (U.S. Pat. No. 3,013,054) and 4-phenoxybenzoic acids (French Pat. No. 1,502,538) substituted phenoxybenzoic acids (U.S. Pat. Nos. 3,979,437 and 4,164,409) and certain 4-trifluoromethyl-4' nitrodiphenyl ethers (U.S. Pat. Nos. 3,928,416, 4,046,798, and 4,063,929). It is the discovery of this invention, however, that certain herbicidal 4-trifluoromethyl-3'-oxygen-substituted-4'substituted diphenyl ethers are very effective herbicides.